Abstract

Extreme ultravioletlithography (EUVL) is currently being examined for its potential use in the next generation of lithography techniques. Among the core EUVL technologies, mask fabrication is of considerable importance due to the use of new reflective optics. This study investigated the etching properties of EUVL mask materials, such as antireflection coating (ARC), TaN (absorber layer) and Ru (buffer/capping layer), by varying the gas flow ratio, dc self-bias voltage and top electrode power in inductively coupled plasma. The (ARC) layer could be etched with an etch selectivity approaching 0.5 over the TaN absorber layer. The ARC/TaN stack could be etched with an infinitely high etch selectivity over the Ru layer. Etching of the stacked mask structures with a line/space hydrogen silsesquioxane e-beam resist pattern showed a profile angle of 85° and an etch stop on the Ru buffer/capping layer.

Received 04 October 2007Accepted 03 March 2008Published online 01 July 2008

Acknowledgments:

This study was supported in part by the EUVL R&D Research Fund of MOCIE and in part by the Second Stage of Brain Korean 21 Project in 2006 program through the Ministry of Education. We also thank Dr. Seung-Sue Kim at Samsung Electronics for his help.